M11 code 431 ISS is the Cummins troubleshooting document for the Idle Validation Switch Circuit fault (PID P091, SPN 91, FMI 2, SRT 00-611). The idle validation switch tells the ECM when the accelerator pedal is released or depressed, and this ISS branch covers pedals where an integrated sensor/switch on the accelerator pedal assembly performs that function. It sets a yellow warning lamp and lists the exact conditions, causes, and step-by-step checks a technician follows.
Official document details
| Brand | Cummins |
|---|---|
| Model coverage | Cummins M11 CELECT electronic engines built 1990 to 1994 |
| System / Group | M11 CELECT (1990-94) |
| Fault identifiers | PID P091, SPN 91, FMI 2, SRT 00-611 |
| Warning lamp | Yellow |
| Pages | 6 |
| Format | |
| Language | English |
Document table of contents
- Circuit description
- Component location
- Shop Talk
- Step-by-step troubleshooting steps
- Fault code clearing and verification
Trucks covered by M11 code 431 ISS
This procedure applies to Cummins M11 CELECT electronic engines built 1990 to 1994. The procedure carries the Cummins fault identifiers PID P091, SPN 91, FMI 2, SRT 00-611 for reference and repair-time tracking. It is set by a loose connection, an uncalibrated accelerator pedal, or an idle validation switch that is wired incorrectly, and typical effects include inconsistent on-idle and off-idle recognition until the integrated switch and wiring are corrected. For engine specifications and dealer support, see the official Cummins website.
Who needs this M11 code 431 ISS manual
Heavy-truck technicians, fleet maintenance teams, and workshop owners diagnosing this fault use it to confirm the code before replacing parts. During diagnosis the integrated sensor/switch sits on the accelerator pedal assembly, and its three circuit wires should be inspected before the OEM harness is replaced. The step-by-step tree starts by reading active and inactive codes with the diagnostic tool, then inspects the harness and connector pins for bent, corroded, pushed-back, or expanded pins, flushing them with electronic contact cleaner Part Number 3824510 before any component is condemned. Test leads run around the bulkhead are used to isolate a faulty OEM harness, and the code is rechecked and cleared once the repair passes.
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Applies to these truck models
This is the manufacturer document shared across 2 model families. It applies to:
- Cummins DTCs
- Cummins M11 CELECT (1990-94)
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